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Abstract:

A coated article includes a substrate, an anti-corrosion layer formed on
the substrate, a decorative layer formed on the anti-corrosion layer. The
substrate is made of aluminum or aluminum alloy. The anti-corrosion layer
is a silicon layer. The coated article has improved corrosion resistance.

Claims:

1. A coated article, comprising: a substrate, the substrate being made of
aluminum or aluminum alloy; an anti-corrosion layer formed on the
substrate, the anti-corrosion layer being a silicon layer.

2. The coated article as claimed in claim 1, wherein the coated article
further comprises a decorative layer formed on the anti-corrosion layer.

3. The coated article as claimed in claim 2, wherein the decorative layer
is a titanium nitride layer.

4. The coated article as claimed in claim 2, wherein the decorative layer
is a chromium nitride layer.

5. The coated article as claimed in claim 2, wherein the decorative layer
has a thickness of about 1.0 μm to about 3.0 μm.

6. The coated article as claimed in claim 1, wherein the anti-corrosion
layer has a thickness of about 3 μm to about 10 μm.

7. A method for making a coated article, comprising: providing a
substrate, the substrate being made of aluminum or aluminum alloy;
magnetron sputtering an anti-corrosion layer on the substrate, the
anti-corrosion layer being a silicon layer.

8. The method as claimed in claim 7, wherein magnetron sputtering the
anti-corrosion layer uses argon gas as the sputtering gas and the argon
gas has a flow rate of about 100 sccm to about 200 sccm; magnetron
sputtering the anti-corrosion layer is carried out at a temperature of
about 100.degree. C. to about 150.degree. C.; uses silicon targets and
the silicon targets are supplied with a power of about 2 kw to about 8
kw; a negative bias voltage of about -50 V to about -100 V is applied to
the substrate and the duty cycle is from about 30% to about 50%.

9. The method as claimed in claim 8, wherein magnetron sputtering the
anti-corrosion layer takes about 90 min to about 180 min.

10. The method as claimed in claim 7, wherein the method further
comprises magnetron sputtering a decorative layer on the anti-corrosion
layer.

11. The method as claimed in claim 10, wherein magnetron sputtering the
decorative layer uses nitrogen as the reaction gas and nitrogen has a
flow rate of about 20 sccm to about 170 sccm; argon gas as the sputtering
gas and argon gas has a flow rate of about 100 sccm to about 200 sccm;
magnetron sputtering the decorative layer is carried out at a temperature
of about 100.degree. C. to about 150.degree. C.; uses titanium or
chromium targets and the titanium or chromium targets are supplied with a
power of about 8 kw to about 10 kw; a negative bias voltage of about -50
V to about -200 V is applied to the substrate and the duty cycle is from
about 30% to about 50%.

12. The method as claimed in claim 11, wherein vacuum sputtering the
decorative layer takes about 20 min to about 30 min.

Description:

CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application is one of the eleven related co-pending U.S.
patent applications listed below. All listed applications have the same
assignee. The disclosure of each of the listed applications is
incorporated by reference into all the other listed applications.

TABLE-US-00001
Attorney
Docket No. Title Inventors
US 34965 COATED ARTICLE AND METHOD HSIN-PEI
FOR MAKING THE SAME CHANG et al.
US 34966 COATED ARTICLE AND METHOD HSIN-PEI
FOR MAKING THE SAME CHANG et al.
US 34967 COATED ARTICLE AND METHOD HSIN-PEI
FOR MAKING THE SAME CHANG et al.
US 34969 COATED ARTICLE AND METHOD HSIN-PEI
FOR MAKING THE SAME CHANG et al.
US 36035 COATED ARTICLE AND METHOD HSIN-PEI
FOR MAKING THE SAME CHANG et al.
US 36036 COATED ARTICLE AND METHOD HSIN-PEI
FOR MAKING THE SAME CHANG et al.
US 36037 COATED ARTICLE AND METHOD HSIN-PEI
FOR MAKING THE SAME CHANG et al.
US 36038 COATED ARTICLE AND METHOD HSIN-PEI
FOR MAKING THE SAME CHANG et al.
US 36039 COATED ARTICLE AND METHOD HSIN-PEI
FOR MAKING THE SAME CHANG et al.
US 36040 COATED ARTICLE AND METHOD HSIN-PEI
FOR MAKING THE SAME CHANG et al.
US 36041 COATED ARTICLE AND METHOD HSIN-PEI
FOR MAKING THE SAME CHANG et al.

BACKGROUND

[0002] 1. Technical Field

[0003] The present disclosure relates to coated articles and a method for
making the coated articles.

[0006] The standard electrode potential of aluminum or aluminum alloy is
very low. Thus the aluminum or aluminum alloy substrates may often suffer
galvanic corrosions. When the aluminum or aluminum alloy substrate is
coated with a decorative layer such as a titanium nitride (TiN) or
chromium nitride (CrN) layer using PVD, the potential difference between
the decorative layer and the substrate is high and the decorative layer
made by PVD will often have small openings such as pinholes and cracks,
which can accelerate the galvanic corrosion of the substrate.

[0007] Therefore, there is room for improvement within the art.

BRIEF DESCRIPTION OF THE FIGURE

[0008] Many aspects of the coated article and the method for making the
coated article can be better understood with reference to the following
drawings. The components in the drawings are not necessarily drawn to
scale, the emphasis instead being placed upon clearly illustrating the
principles of the coated article and the method. Moreover, in the
drawings like reference numerals designate corresponding parts throughout
the several views. Wherever possible, the same reference numbers are used
throughout the drawings to refer to the same or like elements of an
embodiment.

[0009] FIG. 1 is a cross-sectional view of an exemplary coated article;

[0010] FIG. 2 is a schematic view of a vacuum sputtering device for
fabricating the coated article in FIG. 1.

DETAILED DESCRIPTION

[0011] FIG. 1 shows a coated article 10 according to an exemplary
embodiment. The coated article 10 includes a substrate 11, an
anti-corrosion layer 13 formed on the substrate 11, and a decorative
layer 15 formed on the anti-corrosion layer 13. The coated article 10 may
be used as housing for a computer, a communication device, or a consumer
electronic device.

[0012] The substrate 11 is made of aluminum or aluminum alloy.

[0013] The anti-corrosion layer 13 is a silicon (Si) layer and has a
thickness of about 3 μm to about 10 μm.

[0014] The decorative layer 17 may be a titanium nitride (TiN) or chromium
nitride (CrN) layer. The decorative layer 17 has a thickness of about 1.0
μm to about 3.0 μm. A vacuum sputtering process may be used to form
the anti-corrosion layer 13 and the decorative layer 15.

[0015] FIG. 2 shows a vacuum sputtering device 20, which includes a vacuum
chamber 21 and a vacuum pump 30 connected to the vacuum chamber 21. The
vacuum pump 30 is used for evacuating the vacuum chamber 21. The vacuum
chamber 21 has silicon targets 23, titanium or chromium targets 24 and a
rotary rack (not shown) positioned therein. The rotary rack holding the
substrate 11 revolves along a circular path 25, and the substrate 11 is
also rotated about its own axis while being carried by the rotary rack.

[0016] A method for making the coated article 10 may include the following
steps:

[0017] The substrate 11 is pretreated. The pre-treating process may
include the following steps: electrolytic polishing the substrate 11;
wiping the surface of the substrate 11 with deionized water and alcohol;
ultrasonically cleaning the substrate 11 with acetone solution in an
ultrasonic cleaner (not shown), to remove impurities such as grease or
dirt from the substrate 11. Then, the substrate 11 is dried.

[0018] The substrate 11 is positioned in the rotary rack of the vacuum
chamber 21 to be plasma cleaned. The vacuum chamber 21 is then evacuated
to about 1.0×10-3 Pa. Argon gas (abbreviated as Ar, having a
purity of about 99.999%) is used as the sputtering gas and is fed into
the vacuum chamber 21 at a flow rate of about 250 standard-state cubic
centimeters per minute (sccm) to about 500 sccm. A negative bias voltage
in a range from about -300 volts (V) to about -800 V is applied to the
substrate 11. The plasma then strikes the surface of the substrate 11 to
clean the surface of the substrate 11. The plasma cleaning of the
substrate 11 takes about 3 minutes (min) to about 10 min. The plasma
cleaning process enhances the bond between the substrate 11 and the
anti-corrosion layer 13.

[0019] The anti-corrosion layer 13 is vacuum sputtered on the plasma
cleaned substrate 11. Vacuum sputtering of the anti-corrosion layer 13 is
carried out in the vacuum chamber 21. The vacuum chamber 21 is heated to
a temperature of about 100° C. to about 150° C. Ar is used
as the sputtering gas and is fed into the vacuum chamber 21 at a flow
rate of about 100 sccm to about 200 sccm. The silicon targets 23 are
supplied with electrical power of about 2 kw to about 8 kw. A negative
bias voltage of about -50 V to about -100 V is applied to the substrate
11 and the duty cycle is from about 30% to about 50%. Deposition of the
anti-corrosion layer 13 takes about 90 min to about 180 min.

[0020] The decorative layer 15 is vacuum sputtered on the anti-corrosion
layer 13. Vacuum sputtering of the decorative layer 17 is carried out in
the vacuum chamber 21. Nitrogen (N2) is used as the reaction gas and
is fed into the vacuum chamber 21 at a flow rate of about 20 sccm to
about 170 sccm. Silicon targets 23 are powered off and titanium or
chromium targets 24 are supplied with electrical power of about 8 kw to
about 10 kw. The flow rate of Ar, temperature of the vacuum chamber 21
and the negative bias voltage are the same as vacuum sputtering of the
anti-corrosion layer 13. Deposition of the decorative layer 15 takes
about 20 min to about 30 min. The decorative layer 17 is a TiN or CrN
layer.

EXAMPLES

[0021] Experimental examples of the present disclosure are described as
followings.

[0024] The plasma cleaning of the substrate 11 took place, wherein Ar was
fed into the vacuum chamber 21 at a flow rate of about 280 sccm, a
negative bias voltage of about -300 V was applied to the substrate 11.
The plasma cleaning of the substrate 11 took about 9 min.

[0025] Sputterring to form the anti-corrosion layer 13 took place, wherein
the vacuum chamber 21 was heated to a temperature of about 100° C.
Ar was fed into the vacuum chamber 21 at a flow rate of about 100 sccm.
The silicon targets 23 are supplied with a power of about 2 kw, and a
negative bias voltage of about -50 V was applied to the substrate 11.
Deposition of the anti-corrosion layer 13 took about 100 min.

[0026] Sputterring to form the decorative layer 15 took place, wherein
N2 was fed into the vacuum chamber 21 at a flow rate of about 60
sccm. The titanium or chromium targets 24 are supplied with a power of
about 8 kw. Other conditions are substantially the same as vacuum
sputtering of the anti-corrosion layer 13. The deposition of the
decorative layer 15 took about 20 min. Decorative layer 15 has a
thickness of about 1.0 μm.

Example 2

[0027] The vacuum sputtering device 20 in example 2 was the same in
example 1.

[0028] The substrate 11 is made of aluminum alloy.

[0029] The plasma cleaning of the substrate 11 took place, wherein Ar was
fed into the vacuum chamber 21 at a flow rate of about 300 sccm, a
negative bias voltage of about -400 V was applied to the substrate 11.
The plasma cleaning of the substrate 11 took about 9 min.

[0030] Sputterring to form the anti-corrosion layer 13 took place, wherein
the vacuum chamber 21 was heated to a temperature of about 120° C.
Ar was fed into the vacuum chamber 21 at a flow rate of about 200 sccm.
The silicon targets 23 are supplied with a power of about 5 kw, and a
negative bias voltage of about -100 V was applied to the substrate 11.
Deposition of the anti-corrosion layer 13 took about 80 min.

[0031] Sputterring to form the decorative layer 15 took place, wherein
N2 was fed into the vacuum chamber 21 at a flow rate of about 80
sccm. The titanium or chromium targets 24 are supplied with a power of
about 9 kw. Other conditions are substantially the same as vacuum
sputtering of the anti-corrosion layer 13. The deposition of the
decorative layer 15 took about 30 min. Decorative layer 15 has a
thickness of about 1.5 μm.

Example 3

[0032] The vacuum sputtering device 20 in example 3 was the same in
example 1.

[0033] The substrate 11 is made of aluminum alloy.

[0034] The plasma cleaning of the substrate 11 took place, wherein Ar was
fed into the vacuum chamber 21 at a flow rate of about 450 sccm, a
negative bias voltage of about -500 V was applied to the substrate 11.
The plasma cleaning of the substrate 11 took about 9 min.

[0035] Sputterring to form the anti-corrosion layer 13 took place, wherein
the vacuum chamber 21 was heated to a temperature of about 150° C.
Ar was fed into the vacuum chamber 21 at a flow rate of about 150 sccm.
The silicon targets 23 are supplied with a power of about 2 kw, and a
negative bias voltage of about -150 V was applied to the substrate 11.
Deposition of the anti-corrosion layer 13 took about 100 min.

[0036] Sputterring to form the decorative layer 15 took place, wherein
N2 was fed into the vacuum chamber 21 at a flow rate of about 120
sccm. The titanium or chromium targets 24 are supplied with a power of
about 10 kw. Other conditions are substantially the same as vacuum
sputtering of the anti-corrosion layer 13. Deposition of the decorative
layer 15 took about 20 min. The decorative layer 15 has a thickness of
about 1.2 μm.

[0037] When the coated article 10 is in a corrosive environment, the
anti-corrosion layer 13 can slow down corrosion of the substrate 11 due
to the insulating property of the anti-corrosion layer 13. Thus, the
corrosion resistance of the coated article 10 is improved. The decorative
layer 15 has stable properties and gives the coated article 10 a long
lasting pleasing appearance.

[0038] It is believed that the exemplary embodiment and its advantages
will be understood from the foregoing description, and it will be
apparent that various changes may be made thereto without departing from
the spirit and scope of the disclosure or sacrificing all of its
advantages, the examples hereinbefore described merely being preferred or
exemplary embodiment of the disclosure.